On Tue, 15 Aug 2000, Miguel Angel Heredia Moreno wrote:

> Further, I need this device to hook up to a Radio, those ones like the taxi
> drivers use, I guess they work on FM, and send their data over these lines.
> This is where the modem fits in.

You will of course need to take into account regulatory requirements for
wherever you are (FCC in the US, etc) but I would look at packet radio
TNCs.  You send serial data, the TNC establishes an X.25-like connection
with error correction, trtransmit, etc.  Take a look at:

http://www.kantronics.com/

to see some of what is available for wireless modems.  Tekk also makes UHF
data radios with the TNC built in:

http://ameradio.com/business_datacomm.htm#Tekk

Apparently Tekk doesn't have its own web site up yet.

If you want to do it REALLY cheap and have lots of time, you could use
something like an XR2211 or similar modem chip to send data via radio, but
then you have issues with multiple remotes transmitting at the same time,
etc. - plus you get to design a new communication protocol!  What fun.

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
                -- Isaac Asimov

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